Overlay Zoning

Zoning regulations specify the land uses allowable in a certain area. Zoning can be used as a source water protection technique. The types of zoning ordinances available to source water protection planners include:

Overlay zoning

Cluster and planned unit development

Prohibition of various uses

Special or conditional use permits

Performance standards

Transfer of development rights

A Wellhead Protection Overlay zone is established for the purpose of protecting public water supply wells from contamination by land use activities occurring or which may occur within the delineated recharge areas for such wells.

Typical goals for this zoning district are:

Protect human life and health.

Insure that the public is provided with a sustainable, safe potable water supply.

Minimize expenditure of public money for pollution remediation projects.

Minimize regulations on land use.

Minimize business interruptions.

In an overlay district, boundaries for an area are defined and local ordinances and bylaws enacted to protect or limit specific land uses with the area. Such a district “overlies” and supercedes existing zoning for an areas.

An overlay district may cover all or part of a regular zone or zones.

All of the provisions of the underlying zone remain the same, including use, density, and setbacks, for example.

What changes is that there are new and additional requirements established by the overlay district to meet source water protection objectives. Overlay zoning can be particularly useful for adopting additional wellhead protection and water supply watershed zones. Creating a source water protection overlay district may involve such measures as restricting the use of septic systems or limiting development to low-density residential.

An advantage of using an overlay zone is that it can target changes to source water protection areas alone, and allow uses outside the zone to continue.

Overlay districts enforce additional zoning restrictions on top of underlying zoning. Land uses in overlay districts must then conform to the restrictions set for both zones. This approach can be used to identify and set additional protective measures such as impervious cover thresholds for water supply watersheds, wellhead protection areas, floodplains, wetlands, and significant ground-water recharge areas.

Overlay Zoning Examples in Pennsylvania

The Wellhead Protection District as established in the Wellhead Protection Ordinance No. 1 of 2010, shall be incorporated herein and made a part of by reference, as an overlay zone.

Purpose

The purpose of the Wellhead Protection District is to safeguard the public health, safety and welfare, by providing regulation of land use and the manufacture, use, storage, transport, or disposal of hazardous and other substances which pose a threat to the quality and quantity of groundwater being extracted from the South Middleton Township municipal wells. It is the further intent of this District to recognize and protect a uniquely vulnerable groundwater resource area, defined by a carbonate geologic formation which is prone to the development of sinkholes and fractures that allow rapid infiltration of contaminants to these wells.

The Shrewsbury Borough Council developed a wellhead protection program that protects the groundwater underlying the community water supply, which consists of several wells located throughout the borough and Shrewsbury Township.

Groundwater is currently the sole source of public water. It is not an infinitely renewable resource. Growth threatens to deplete the available groundwater supply through excess demand and inhibits the recharge capability of the area through exorbitant impervious areas and competing resource uses.

Accidental spills and discharges of toxic and regulated substances can threaten the quality of our water, posing public health and safety hazards. These hazards are a greater threat because of the increasing land development, population and vehicular traffic all through our region but especially in the vicinity of our wellheads.

Click here to see the borough ordinance establishing a wellhead protection overlay district.

The borough’s Zoning Officer was given the responsibility for administration and enforcement of the ordinance. click here for a list of regulated uses in a wellhead protection district.

A. Purpose – The borough and its residents depend exclusively on groundwater for a safe drinking water supply. The borough has developed and owns the drinking water wells utilized by the borough, which are located upon a parcel of land adjacent to the corporate boundary of the borough. Certain land use practices and activities outside and within the borough can seriously threaten or degrade groundwater quality. The purpose of this chapter is to protect the public health, safety and welfare through the preservation of the groundwater resources of the borough public water supplies and to ensure a future supply of safe and healthful drinking water for the residents of the borough. The designation of the Wellhead Protection Overlay District, as provided hereinbelow, and the regulation of activities within such Wellhead Protection Overlay District will reduce the potential for ground and surface water contamination of the borough-owned water wells and thereby preserve irreplaceable groundwater resources. The delineation of the Wellhead Protection Overlay District and the development of the provisions of this chapter are based upon a professional study of the hydrogeologic and other features of the borough and contiguous areas conducted for the benefit of the borough and certain nearby municipalities.

B. This chapter is enacted pursuant to the authority contained in Article I, Section 27, of the Constitution of the Commonwealth of Pennsylvania and Sections 501, 503, 601, 604(1), and 603(b) of the Pennsylvania Municipalities Planning Code, Act 247 of 1968, as amended by Act 170 of 1988, as amended by Act 209 of 1990, and as further amended by Act 131 of 1992, which provisions authorize the borough to enact ordinances regulating development and land uses to ensure the public health and safety, provide a safe, reliable and adequate water supply and preserve natural values and aquifers.